On Monday, Google announced the second-biggest acquisition in its history. The tech giant shelled out &dollar;3.2 billion for smart-thermostat manufacturer Nest Labs of Palo Alto, California. But what does Google want with your central heating? And what could this mean for the future of “smart homes”?

“Nest has always been a company that’s been interested not just in devices but also the data and algorithms behind them,” says Sara Watson at Harvard University’s Berkman Center for Internet and Society. “Obviously that’s going to pique Google’s interest.”

Advertisement

The Nest thermostat is designed to learn when and how you like to heat your home. After a 12-day set-up period, the device has learned your basic schedule, is able to turn the heating on and off intelligently, and in the process it attempts to save you energy by only firing up the boiler when you really need it.

Watson believes Google is now a company obsessed with viewing everyday activities as “information problems” to be solved by machine learning and algorithms. Google’s fleet of self-driving vehicles is just one example. The home is no different, and a Google-enabled smart home of the future, using a platform such as the Google Now app – which already gathers data on users’ travel habits – could adapt energy usage to your life in even more sophisticated ways.

“Imagine Google Now knows you’re on your way home,” suggests Watson. “The thermostat can predict that you’re going to be home in 10 minutes and it can get the heat going.”

Power crazy

Daniel Obodovski, co-author of The Silent Intelligence&colon; The internet of things, points out that Google previously expressed an interest in gathering data on energy use. However, that project, Google PowerMeter, was canned in 2011 .

“They tried to measure the consumption of energy,” says Obodovski. “Now they have the missing piece of the puzzle. Now they have the thermostat that can regulate the cooling and heating and see who is at home and who is not at home.”

Google’s plans for Nest or any other future smart-home devices are not yet public knowledge. Indeed, Nest’s CEO, Tony Fadell, has said that for now he won’t share data about Nest’s customers with Google.

Many expect that will change in the future. Watson points to Google’s revised privacy policy of 2012, which allowed the company to analyse data on users across different platforms.

“Google’s entire data policy skews towards a consolidated view of one consumer. It seems pretty likely that that would be a future direction for any acquired company of Google’s,” she says.

Privacy at risk

Whether or not that does happen, some are already expressing concerns over how smart-home companies might “profile” those who use their technology.

George Danezis studies privacy engineering at University College London. He argues that if Google ever launched a device that gathered data on electricity use in a home, they could theoretically surmise a great deal about the people that live there. “A household may follow a very ritualistic schedule, such as during Ramadan, for example,” he says. “Most religions have holidays where you are meant to have a big gathering so these will show up if there is a lot of cooking, say, during certain Jewish festivals.”

In addition, there are methods of inferring what devices are being used in a home at a given moment. It’s an aspect of “non-intrusive load monitoring”, whereby the energy signatures of individual devices like your washing machine or TV can be picked up as part of the overall energy input to the house.

Movie stalker

Researchers in 2011 were even able to use a similar approach to determine what movie was being watched on a television set by making energy profiles of each film. This was achieved by observing that a television’s electricity load will vary over time depending on whether dark or light scenes are being displayed to the viewer.

Although the researchers in question relied on very granular data from the television set, Danezis worries that such techniques could one day offer smart-home companies an X-ray view of your home.

Many, though, are more positive about the prospect of Google-controlled smart-home technology. “I’m excited about it,” says Obodovski. “Instead of us adjusting to our homes, our homes will adjust to us.”